Solid material withdrawing arrangements for vertical furnaces



July 7, 1959 F. P. SOMOGYI 2,893,576

SOLID MATERIAL WITHDRAWING ARRANGEMENTS FOR VERTICAL FURNACES Filed Nov.25, 1956 Inventor:

FRANCIS mm SnMo 6Y1 15 TI'UR/VE) United States Patent "ice SOLIDMATERIAL WITHDRAWING ARRANGE- MENTS FOR VERTICAL FURNACES Francis PaulSomogyi, London, England Application November 23, 1956, Serial No.624,043

Claims priority, application Great Britain November 25, 1955 4 Claims.(Cl. 21418) In vertical furnaces as used heretofore the loose materialfed into the top is raised to such a temperature that agglomerationtakes place and the customary device for extracting the material at thebottom is a crushing grate which will break up the agglomeratedmaterial, the broken pieces then falling out through openings in thecrushing grate.

More recently techniques have been developed whereby the temperature ofthe furnace can be accurately controlled and with certain applicationsit is desirable to control the temperature so that sintering of theindividual preformed shapes fed into the furnace, takes place without ageneral melting and agglomeration of the whole feed.

The drawback inherent in extraction grates as heretofore used thenbecomes apparent in that the relatively loose material in the furnaceruns right through without any control.

.The invention consists of an arrangement for withdrawing solid materialfrom a vertical furnace, comprising a crushing grate, an upwardlypointing conical member mounted below the crushing grate to receive thesolid material and guide its flow outwardly and downwardly to an annulargap between the edge of the base of the conical member and the furnacewalls and an annular shelf adjacent the furnace walls below said gap andextending radially inwardly beyond the edge of the base of the conicalmember to receive the solid material and guide its flow inwardly to fallthrough the central aperture of the annular shelf.

When the cone is stationary the static angle of repose of the materialon the annular shelf is such that the material is prevented from runningout but when the cone is oscillated or rotated, the angle of repose isreduced to the dynamic angle of repose and the material is discharged ata rate depending on the degree of agitation imparted to the solidmaterial.

This effect can be increased by the addition of fork or plough membersarranged for rotation around the vertical axis of the furnace andextending into the bed of mate rial and operated from the grate drive orfrom an auxiliary driving arrangement.

The invention will be further described with reference to an embodimentshown in the accompanying drawing which is a section of the base of avertical furnace having an extracting arrangement in accordance with theinvention.

In the drawing the vertical furnace wall 1 is closed at the bottom by anannular plate 2 having a central orifice leading to an extraction shaft3.

Projecting through the base of the furnace is a driven vertical shaft 4which drives at its top end within the furnace a crushing grate 5 whichmay be of known construction. Below grate 5 and attached thereto ismounted a conical shell 6 having plough members 7 secured at spacedintervals around the circumference of its base,

2,893,576 Patented July 7, 1959 Between the plate 2 and conical shell 6is an annular plate 8 extending radially inwardly beyond the edge of thebase of the conical shell but leaving a circular aperture around theshaft 4.

-In operation, when shaft 4 is rotated or oscillated by suitable means(not shown) the solid material 9 in the furnace is crushed, should someagglomeration have occurred, and flows around and through the grate 5into the space between the frusto-conical shell wall of 6 and the walls1 of the furnace. It then flows around the outer edge of the member 6onto the shelf formed by the plate 8 and then radially inwardly to theaperture in the centre of the plate and thence down into the extractionshaft 3.

The ploughs 7 aid the movement of solid material. Narrow slots 6a may beprovided in the shell 6 to allow the passage of an air or other blastinto the furnace.

The vertical distance from the edge of the base of the cone to the shelf8 below it and the horizontal distance from the edge of the base of thecone to the inner edge 8' of the plate 8 will be so arranged to providethe necessary discrimination between static and dynamic angle of reposefor the solid material being extracted.

The angle of the cone is about 45 and should be such as to allow flow ofsolid material under all conditions.

Various modifications may be made within the scope of the invention.

I claim:

1. Arrangement for controlling the discharge of relatively loose solidmaterial from the lower end of a vertical sintering furnace into anextraction shaft comprising in combination at the lower end of thefurnace above said extraction shaft a rotatable crushing grate providedwith openings of a size insuflicient to retain the material on saidgrate, an upwardly pointed conical member rotatably mounted adjacent toand below said grate and adapted to receive the solid material passingthrough the said grate and to guide its flow outwardly and downwardly toan annular gap between the edge of the base of said conical member andthe furnace walls, thereby intercepting a direct passage of the materialfrom the grate into said extraction shaft, a stationary annular shelfprovided with a central aperture and arranged adjacent the furnace wallsbelow said gap and extending radially inwardly beyond the edge of thebase of the conical member to receive the solid material passing throughsaid gap and to guide its flow inwardly to fall through said centralaperture into said extraction shaft, said annular shelf being of aradial width suflicient to retain the material received thereon in itsstatic angle of repose, but insufficient to retain the same in itsdynamic angle of repose, and means for rotating said conical member.

2. An arrangement as claimed in claim 1, provided with plough membersarranged to extend into the bed of material received on the annularshelf, said plough members being rotatable around the vertical axis ofthe furnace.

3. An arrangement as claimed in claim 2, in which the plough members aremounted at spaced intervals around the circumference of the base of theconical member.

4. An arrangement as claimed in claim 1, in which narrow slots areprovided in the conical member to allow the passage of air or otherblast.

References Cited in the file of this patent UNITED STATES PATENTS399,795 Taylor Mar. 19, 1889 989,661 Sundstrom Apr. 18, 1911 2,667,409Hubmann Jan. 26, 1954

